Most of the videos, movies, TV shows, trailers, live streams hosted on YouTube is now available in ultra high definition (UHD) and high definition (HD) format, such as 8K (4320p), 5K (288p), 4K (2160p), 1440p, 1080p, and 720p. However, when viewing the video playback, YouTube may choose to play the video at the SD resolution of 480p, 360p, 240p or 144p, despite the source is available in HD resolution.

YouTube adjusts the playback quality of video stream between standard definition (such as 240p or 360p) and high definition (720p or 1080p) based on the speed of the Internet connection (bandwidth), and almost never in 4K UHD or above quality automatically.

YouTube viewers can always change the video quality in Settings of the video player, however, it’s annoying to have to change the playback quality if YouTube is unable to detect your available Internet bandwidth properly. YouTube no longer provide options to set preferred video quality during playback. Nonetheless, it’s possible to use extensions, add-ons or plugins on web browsers to watch YouTube automatically not only in HD, but in highest resolution possible.

Chrome

There are plenty of extensions for Chrome that can help users to play YouTube videos in HD or UHD automatically. One example is Turn Off the Lights, which among its powerful features for YouTube is ability to set the quality of YouTube videos automatically.